Field of the Invention
The present invention relates to a developer carrying member to be used in an electrophotographic image forming apparatus, and an electrophotographic process cartridge and an electrophotographic image forming apparatus using the developer carrying member.
Description of the Related Art
In an electrophotographic image forming apparatus, a photosensitive member is charged by a charging unit, and an electrostatic latent image is formed on the photosensitive member with a laser. Then, a developer (hereinafter sometimes referred to as “toner”) in a developing container is conveyed by a developing member, and the electrostatic latent image on the photosensitive member is developed with the toner in a portion where the photosensitive member and the developing member are brought into close contact with each other. After that, the toner on the photosensitive member is transferred onto a recording sheet by a transferring unit and fixed onto the recording sheet with heat and a pressure. As one of developing members to be used in the above-mentioned developing method, there is given a developer carrying member having such a configuration that an elastic layer is formed on the periphery of a metallic core, and a single surface layer or a plurality of surface layers are formed on the elastic layer as required.
In an image forming apparatus of a nonmagnetic one-component contact developing system, an electroconductive electrophotographic member having an electric resistance of from 103 Ω·cm to 1010 Ω·cm is generally used as the developer carrying member.
In recent years, the performance required of the developing member to be used in an apparatus adopting an electrophotographic system has been becoming higher, and from the viewpoints of high image quality and high durability, a developing member such as a two-layer developer carrying member including a surface layer on a surface of an elastic layer has come into widespread use.
As the surface layer of the developing member, a urethane resin excellent in wear resistance and charge imparting property to a toner is widely used. In recent years, in order to further enhance a function, there has been proposed an improvement method for the surface layer. Japanese Patent Application Laid-Open No. 2011-186433 discloses a technology of enhancing scratch resistance and the speed of damage restoration by incorporating an acrylic resin into a urethane resin. Further, Japanese Patent Application Laid-Open No. 2014-29499 discloses a technology of enhancing deformation recoverability and filming resistance by incorporating an acrylic resin into a polyether-based urethane resin having a particular structure.
In view of the foregoing, the present invention provides a developer carrying member in which a ghost or filming is less liable to occur even in a severe environment.
Further, the present invention provides an electrophotographic image forming apparatus and an electrophotographic process cartridge that contribute to stable output of an electrophotographic image of high quality.